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Pressure mounts to release video of Charlotte shooting

Investigators in Charlotte face mounting pressure to release video footage of the police shooting of an African American man, after protesters defied a curfew and took to the North Carolina city's streets for a third straight night.

The death on Tuesday of 43-year-old Keith Lamont Scott was the latest in a seemingly steady string of police-involved killings of black men that have fuelled outrage across America.

The victim's family -- who like many in Charlotte dispute the assertion that Scott was armed -- have viewed police footage of his shooting and are leading calls for it to be made public.

But police here are refusing so far to release the dashcam video, arguing among things that this might interfere with a parallel state probe into the incident.

Their handling of the case stands in stark contrast to a similar police shooting last Friday involving an African American man in Tulsa, Oklahoma.

There, the video has been released and the white officer involved has already been charged with first degree manslaughter.

Charlotte Mayor Jennifer Roberts said Friday she backed the idea of releasing the video -- which has been viewed by Scott's family -- but not just yet.

"I would like to have it released," Roberts told CNN.

But she echoed Charlotte police chief Kerr Putney's argument that care must be taken not to jeopardize the state probe.

One risk, the mayor said, is that if witnesses to the shooting see the video they might change their account of what happened.

City hall is in talks with investigators and "I think it is only a matter of time" before the video is released, Roberts said.

The chorus of calls appealing for the release was joined Friday by the New York Times, which praised police in Tulsa and said the response in North Carolina was wrong.

"There is no legal reason to withhold the video from the public, and in this fraught situation, the best way to allay the community's distrust is complete transparency," the Times said in an editorial.

Also appealing for the release are the American Civil Liberties Union and the NAACP, the US black community's main civil rights organization.

Scott was shot and killed in an apartment complex parking lot during an encounter with police officers searching for another person wanted for arrest.

Police say Scott was armed with a handgun while his family says he was holding a book.

No gun is visible in the video, which shows Scott stepping backward when he was shot, one of the family lawyers told CNN.

"His hands are down by his side. He is acting calm," Justin Bamberg said. "You do see something in his hand, but it's impossible to make out from the video what it is."

Police chief Putney has said a handgun was recovered at the scene, and that no book was found, contrary to the family's assertion.

He says the video footage does not provide "absolute definitive visual evidence that would confirm that a person is pointing a gun."

But the footage indicates the officer identified as having shot Scott -- Brentley Vinson, who is also black -- was justified, he says.

"The officer perceived his failure to comply with commands, failure to drop the weapon and facing the officers as an imminent threat," Putney said on Fox News.

North Carolina's governor has declared a state of emergency in Charlotte, and several hundred National Guard troops and highway police officers were deployed to reinforce local police protecting city infrastructure and businesses.

Mayor Roberts said a midnight curfew in Charlotte will remain in effect Friday night.

In the protests Thursday night, hundreds of people marched to the city police station carrying signs saying "Stop killing us" and "Resistance is beautiful." But the atmosphere was far calmer than the previous two nights.

Several hundred protesters remained on the street following the midnight curfew, but security forces took a hands off approach and did not enforce the restriction.

Protesters held an impromptu vigil on the sidewalk where the man was struck by a bullet from a shooter who remained at large. They lit candles and offered prayers.

The protester, who was shot by a civilian in Wednesday night's protests, died in hospital on Thursday.

A handful of protesters confronted police on Thursday night. However, many marched past officers who posed a less intimidating presence on the streets despite their greater numbers.

"Black lives don't matter in this country," said a 34-year-old protester with a mask around his neck who identified himself only as Amen-Ra.

"We're coming together to make them matter, to force America to make them matter -- either through violence or peacefully."

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Peaceful protesters embrace on the third day of demonstrations in Charlotte. (AAP)